Clothing is a portable micro-environment of the human body. This paper confirms how effective clothing is a tool for the human body to adapt to various climates on the earth from cold to hot. First of all, from a spatial stand point, the relationship between climate and the characteristics of folk costumes throughout the world, and from a perspective of time, the seasonal changes in Japanese clothing culture (koromogae) were briefly summarized. Then, the methods and the results through four different approaches which have conducted in our laboratory in order to develop the functional, climate adaptable and comfortable clothing were introduced. In the behavioral approach on climatic adaptability based on clothing, the dressing behavior of urban residents was examined with a fixed-point observation method using photography in order to survey the connection between clothing and climate in modern society. In the physical approach, the development of thermal/sweating thermal manikins in our laboratory and the evaluation of Cool-Biz products developed by fiber/apparel companies using a sweating thermal manikin “JUN” were introduced. In the physiological approach to develop climate adaptable clothing, physiological basic data on the human body in different climates, especially a distribution of skin temperature and sweating rate over the skin surface were described. In the psychological approach, local thermal sensation and humid sensation over the skin surface were examined and the research methods and the results obtained were briefly introduced.
This paper presents findings on variations in human thermoregulatory response due to demography and anthropometry by studying different subjects during periods of rest, moderate walking and recovery. Sixteen subjects participated in the present study. Controlled experiments were conducted under similar environmental conditions (ambient air temperature and relative humidity). Subjects underwent four phases of experiments : (i) steady- state measurements, (ii) 15-min walk, (iii) 15-min recovery in a sitting position, and (iv) post experiment measurements. There were significant differences in mean skin temperature (Tsk,mean) at rest between genders. However, no significant differences were observed in Tsk,mean between age groups. Core temperatures (Tc) at rest were not significantly different between gender and age groups. Body Mass Index (BMI) and weight were observed to be positively correlated to Tsk,mean of subjects at rest. It was observed that subjects with lower BMI tended to have lower local skin temperatures (Tsk) in their extremities. On the other hand, subjects with higher BMI tended to have slightly lower Tsk in their trunks but higher Tsk in the extremities of their bodies. Elderly male subjects had significantly higher Tsk,mean than other demographic groups in the experiments. Anthropometry of subjects did not influence the change in Tc during moderate walking and recovery period. Although Tsk,mean was observed to generally decrease with BMI during moderate walking, no significant correlation was observed. However, Tsk,mean gain was observed to be marginally dependent on weight and body surface area (BSA) during the recovery period. During the moderate walking phase, subjects with BMI above 23 were observed to have reduced Tsk in a few parts of their body. Conversely, subjects with BMI under 21 experienced increase Tsk across most body parts, especially their extremities. Overall, during moderate walking, sweat rate (SR) was significantly correlated to both BSA and BMI. At similar BMI levels, the SR of males were observed to be greater than that of females. The results show that gender and anthropometric conditions have a significant effect on the thermoregulatory response of subjects at steady-state and during moderate walking. Variation in the Tsk across different demographic and anthropometric groups suggest that these differences have to be considered when considering localized comfort of subjects.
During winter, much of the energy contained within the battery of an electric vehicle is consumed by the air heating system. This energy consumption reduces the cruising distance of an electric vehicle. Additionally, stop-and-go driving, i.e., having many stops while driving, and frequent door opening/closing are typical of the operation of lightweight trucks used by home delivery services in residential areas; these behaviors lead to air exchange between the outside environment and the vehicle interior. This air exchange puts additional burden on the heating system and influences the thermal comfort of the driver. The effect of door opening needs to be investigated to develop a more effective heating system for electric vehicles. In this study, numerical simulations of a right-hand drive vehicle were performed to evaluate the variation in the thermal environment of the vehicle cabin when the door is opened and closed in relatively severe winter temperatures. The result showed that the average vehicle interior air temperature decreased at a rate of 2 °C/s during door movement. The warm interior air rose as it moved outward because of buoyancy. Simultaneously, cold outdoor air flowed into the lower region of the cabin. The total heat loss was approximately 57 kJ when the door was left open for 3 s and 37 kJ when the door was left open for 1 s. The standard new effective temperature (SET＊) of the driver decreased at almost the same rate as the air temperature. The equivalent temperature on the right side of the driver’s body decreased drastically and rapidly as a result of the door opening. In contrast, the equivalent temperature on the left side of the driver’s body decreased more gradually. The equivalent temperature of the driver’s head remained consistent throughout the opening and closing of the door. The equivalent temperature of the driver’s hand, which is a thermally sensitive part of the body, was affected by the air temperature change caused by the door opening. The door movement itself had less to do with these results than the temperature difference between the vehicle interior and the environment. Thus, this discussion is applicable to a wide range of winter situations.The temperature difference is the trigger for the air exchange. The results of this study suggest that heat radiators may be more effective than air heating in improving the thermal comfort experienced by the driver because they do not cause an air temperature difference, which would reduce the amount of air exchange.